Remembrance and forgetfulness. Be content with the old paths.

We have a tendency to forget, and therefore Christians need to be reminded of these 'qualities' (virtues and foundational truths). Peter acknowledges that they already know these things are well established in them, and yet there is a need for them to be reminded of the basic truths of the Gospel. The goal is to stir them up (to arouse and wake up) so that they will not be sluggish and will act upon these old truths. As the commentator John Brown said "action is to be the end result of knowledge". Even the Lord's Supper is intended to be a memorial in which we are called to remembrance.